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B M Rock

Publications and source records attributed to B M Rock.

4 recordsLinked to original sources
PubMed1997

Characterization of single-cell migration using a computer-aided fluorescence time-lapse videomicroscopy system.

Single-cell assays of cell migration, while yielding dynamic measurements of cell position and morphology, are predominantly limited by the time required for data collection and analysis. Computer-aided fluorescence time-lapse videomicroscopy (CAFTiV) was developed in order to facilitate the tracking and rapid examination of large numbers of motile cells. The system combines time-lapse videomicroscopy with epifluorescence capability, which allows full automation of image capture, sorting, and analysis due to the low background in the fluorescence images. Utilizing the CAFTiV system, data analysis time was reduced from over 125 h to less than 1 labor minute. In addition, fluorescence imaging permits cell tracking in small-volume chambers (<100 microL), which is useful should the addition of expensive reagents be required. It is anticipated that the ability to characterize both biochemical and biophysical properties responsible for cell movement will be enhanced by this methodology.

Cell Movement↗
PubMed1997

Two Gq class G proteins are expressed in human keratinocytes.

G proteins link many cell surface receptor generated signals to activation of multiple cellular processes in all tissues. There is specificity in the receptor interaction with the G protein and in the interaction of the specific G protein with different effector molecules. The purpose of this study was to determine some of the biologically relevant G proteins in keratinocytes. The G alpha subunit of the heterotrimeric G protein was investigated because much of the biologic activity and the receptor specificity resides there. A polymerase chain reaction strategy was used that amplified multiple G alpha gene segments between conserved primer sites from keratinocyte first strand cDNA. Two Gq class G proteins, G alpha 16 and G alpha y, were identified. Using northern analysis and in situ hybridization, mRNA of both of these genes were detected in keratinocytes in culture and in epidermal keratinocytes. G alpha y was expressed in multiple other cell types and tissues, but G alpha 16 was restricted in expression to keratinocytes and keratinocyte-derived adnexal structures in the skin. G alpha 16 has previously been reported to be limited in expression to hematopoietic cells. The physiologic receptor to which it couples in neutrophils is reported to be a C5a receptor. The receptor to which it couples in keratinocytes has not been elucidated but by analogy may be another chemokine receptor. We hypothesize that G alpha 16 is an important conduit for responses to inflammatory signals in keratinocytes.

Animals↗
PubMedDate not supplied

Alpha4beta1 and alpha5beta1 control cell migration on fibronectin by differentially regulating cell speed and motile cell phenotype.

Computer-aided time lapse fluorescence videomicroscopy was used to study single cell migration behavior of human aortic endothelial cells on fibronectin coated substrates of varying protein surface density. The role of receptors alpha5beta1, alpha(v)beta3, and alpha4beta1 in mediating cell adhesion and migration on fibronectin was characterized using integrin specific monoclonal antibodies. Matrix density had a direct effect on controlling the proportion of migrating cells and the directional persistence of cell movement (p<0.01). While there was relatively little influence of fibronectin surface density on absolute migration speed, the ability of endothelial cells to disperse over a surface, as measured by the dispersion coefficient, was biphasic with respect to the surface density of this matrix protein (p<0.005). Both cell speed and the proportion of migrating cells was controlled by alpha4beta1 (p<0.01). However, alpha5beta1 selectively regulated the transformation of stationary cells to those exhibiting motile behavior (p<0.05). Migratory responses on fibronectin were not influenced by blockade of the alpha(v)beta3 receptor. It is noteworthy that cell surface adhesive receptors which control commitment to a motile phenotype are not necessarily the same as those that control migration speed.

Antibodies, Monoclonal↗